In South Africa, vast quantities of mine water are produced through mining operations such as gold and coal mining. These mine waters contain high levels of dissolved metals such as iron, aluminium and manganese, as well as other impurities. The mine waters are typically stored above ground, but seepage into underground voids or cavities takes place continually. At the same time, the mine waters become even more polluted through pyrite oxidation that generates high levels of acidity and dissolved sulphates in accordance with reaction (1):4FeS2+15O2+14H2O→4Fe(OH)3+8H2SO4  (1)
The resultant acid mine drainage (AMD) is thus a major contributor to water pollution.